A. Field of the Invention
The present invention relates to a process for preparing calcium enriched food products, particularly beverages, and the products that can be prepared by the process.
B. Description of the Related Art
Calcium is essential to the well being of humans and is continuously utilized by the body. In particular, calcium is used in the body to provide rigidity to the skeletal framework, as a catalyst for the conversion of prothrombin to thrombin, a compound necessary for blood clotting, to increase cell membrane permeability, to activate a number of enzymes including lipase and adenosine triphosphatase, and to act as a component in the mechanisms of neural transmission and muscular contraction.
Calcium can be obtained from a variety of dietary sources. Primary sources of calcium are dairy products, in particular milk, which account for 75% of the daily calcium intake while foods other than dairy products generally contribute less than 200 mg of calcium daily. However, beginning in young adulthood and continuing through later life, the general population may not consume milk in sufficient quantities to obtain the recommended dietary levels of calcium.
Calcium deficiencies have been noted as a major health problem, particularly for women. Osteoporosis, an accelerated bone loss, can occur when the body is deficient in calcium. During a period of calcium deficiency, calcium that is needed for various body functions can be retrieved from bones and thereby prevent bone remodeling. Premenopausal adult women require about 1,000 milligrams of calcium per day (based on recommendations by the 1984 NIH Consensus Development Panel on Osteoporosis). Younger women, particularly pregnant and lactating women and post-menstrual women may require more. Further, adequate calcium intake before age 35 may lessen the effect of osteoporosis in later life.
To provide additional sources of calcium, a variety of calcium supplements have been developed. Calcium carbonate, calcium lactate, and calcium gluconate are commonly used. Calcium carbonate has 40 percent calcium and is generally available in tablet form. Calcium lactate has 13 percent calcium and calcium gluconate has 9 percent calcium. The problems encountered with tablets are that they may be difficult to swallow, or if chewable, can leave an unpleasant "chalky" taste in the mouth.
To meet this situation, the art has developed a number of calcium enriched beverages. Such beverages have ranged from enriched milk products to a sweetener supplement containing soluble calcium, citric acid, malic acid and sugar, as described in U.S. Pat. No. 5,468,506. Fruit juices have received particular attention as a vehicle for providing additional calcium to the diet. For instance, U.S. Pat. No. 4,722,847 describes fruit juice beverages and concentrates by forming a premix solution containing highly soluble calcium citrate and malate species which is then combined with concentrated fruit juice, plus other fruit juice materials. The method is said to provide beverages and concentrates which contain substantial levels of solubilized calcium without generating cooked/browned off-flavors and without including undesirable species such as chloride ions.
U.S. Pat. No. 4,871,554 describes a calcium fortified beverage that contains water, a concentrated fruit juice and a solubilized calcium component derived from a salt blend wherein 50-80% by weight of total calcium is tribasic calcium phosphate and 20-50% by weight of total calcium is calcium lactate. A number of other documents describing calcium enriched beverages is described in the background of the foregoing patents.
The large number of documents describing calcium enriched beverages reflects the difficulty in providing an acceptable product. Calcium compounds can be difficult to dissolve into fruit juice beverages unless expensive mixing equipment is used and can impart undesirable color and/or unpleasant taste to the beverage. Furthermore, certain of the calcium compounds used to enrich the beverages are relatively expensive and significantly increase the cost of the calcium enriched product.